If you've never used clay bar, prepared to be amazed. I use Meguiars, its awesome (but i dont think it matters what brand, i think they're all the same..lol) I just use all Meguiars stuff.

Here are my steps:

1) Wash vehicle GOOD with Meguiars car soap
2) hand dry entire vehicle twice with microfibe towel using a clean dry one on second go round.

find good shady spot to park vehicle when doing this

3)Knead the clay really good and then flatten it in your hand. Now start on one body panel, say the hood and spray a spot with the spray. then rub really well with bar. then go behind that with the included microfiber towel. Do this to the whole body panel. Then once you are done with that, take the BACK of your hand and feel the paint it will be smooth where you clayed at. You can do this in the process of clayying to see spots you missed. Now wax that whole body panel and then remove wax after a few minutes. Wallah you are done with that panel, go the next and repeat all of this step three until you have done whole car